The invention relates to a fuel injection nozzle for internal combustion engines. An injection nozzle of this kind is already known from German laid-open application No. 27 39 628, in which the attachment piece is attached to a measuring device, in order to ascertain the electric resistance between the nozzle needle and the valve seat and to indicate the movement of the nozzle needle relative to the valve seat. In this nozzle, the valve seat is connected to ground and the nozzle needle is connected to the positive pole of the vehicle electrical system, and connecting the attachment piece electrically to the nozzle needle is accomplished via the compression body and the closing spring. While a connection of this kind requires few structural parts, in practice it does not satisty all the requirements made upon it, because the fuel film between the parts is utilized as a means of insulation.